Investigation of the parameters affecting the cold forming process with Rollform by numerical methods

The rollform process is one of the rare processes that can incorporate many different operations such as drilling, unloading, welding and cutting by integrating a wide variety of units. In addition, the rollform process has many advantages over molding. The ability of the rollform process to produce profiles without any length limit, the ability to shape high-strength steels, and the fact that it is a fast process are just some of these features. At the beginning of the thesis, these subjects and the place and importance of the rollform process in the automotive sector were discussed and the automobile parts produced with rollform were emphasized. Accordingly, automobile parts such as front or rear bumpers, rockers or reinforcement elements are produced by the rollform process. In the studies conducted in the literature, both the importance of the rollform process and the produced automobile parts are included. Within the scope of this thesis, with the help of designing different types of U-Profiles with CATIA V5 and transferring these designed U-Profiles to UBECO-PROFIL, a process design and analysis software specialized for rollform, it is aimed for determining the number of stations for U-Profiles, to obtain the bending line stress values, to design the necessary rolls, to obtain the overbending angles according to the springback values. And finally, the stress distribution on the profiles with LS-DYNA using the finite element method is included. In the finite element study, the effects of geometrical differences such as height, thickness and base width on the part were examined, a solid element was used to examine the variation in thickness, and a shell element was used to examine the variation in height and width. All the values of the obtained results were transferred to the excel program and various graphs related to this subject were drawn. The graphs drawn by taking the average of the values taken for each U-profile and each station gave us the change in the average stress value against the length. It has been observed that these effects are observed most clearly with the average stress values, and it has been experienced that some maximum and minimum values can be misleading. Comments about the drawn graphics were shared in the last parts of the thesis, and a result was tried to be reached. In addition to this study, some additional studies that can be done in the future were discussed and the master's thesis was concluded. Keywords: Rollform, finite element analysis, stress, springback, sheet metal forming.